Method for realizing confusing layer in block cipher algorithm

Abstract

The invention provides a method for realizing a confusing layer in a block cipher algorithm. A novel method for realizing an S box based on GF(2<16>) inversion is realized; and by converting a finite field GF(2<16>) and a composite domain GF ((2<8>)<2>), the method reduces storage amount and calculation amount brought by the traditional table look-up method, saves the hardware realizing cost and improves the operation efficiency of the S box based on GF(2<16>) inversion. The method comprises the following steps of: initializing data needing inversion operation on the GF(2<16>); selecting a primitive polynomial on GF (2<8>) for solving a converting matrix of the finite field GF(2<16>) and the composite domain GF ((2<8>)<2>); expressing an initialized element in the GF(2<16>) in the GF (2<8>) by utilizing the converting matrix and carrying out inversion operation in the GF (2<8>); and finally converting an operation result into an element form in the GF(2<16>) by the converting matrix and outputting. Compared with the traditional table look-up algorithm, the scheme provided by the invention has the storage area being only 1 / 512 of the original technology, at least saves 98.57 percent of hardware realizing area and improves speed by 32.96 percent.

Description

technical field [0001] The invention relates to a block cipher encryption and decryption algorithm, in particular to a method for realizing the obfuscation layer in the block cipher algorithm. Background technique [0002] The random obfuscation layer is the core operation layer of the data encryption and decryption algorithm to realize the obfuscation and diffusion of encrypted data. In the block cipher algorithm, the S-box is usually used to realize the nonlinear replacement of the random obfuscation layer. In order to meet the needs of modern information security, the cryptographic design uses a large-scale random obfuscation layer as much as possible to ensure the security and flexibility of data encryption. Among them, based on GF (2 16 ) S-box for inverse calculation has wide application and important role in military communication, satellite data link, next-generation belt Internet security and other fields. Therefore, the research and efficient implementation of su...

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Problems solved by technology

And for There are few researches on the analysis method and efficient implementation technology of inverse S-box

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